Analyses of multi-wavelength data sets on 2002 December 19
at approximately 2150 UT show evidence of a large-scale,
transequatorial coronal eruption associated with
simultaneous flares in active regions in both hemispheres.
The coronal manifestations (based on EIT, LASCO, and TRACE
images) include a large coronal dimming, an
opening/restructuring of magnetic fields, the formation of a
transient coronal hole, and a halo CME. In the chromosphere,
ISOON H-alpha images show distant flare precursor
brightenings and several sympathetic flares. Originating
near the main flare is a rapidly propagating (800 km/s),
narrowly channeled disturbance detectable as a sequential
brightening of numerous pre-existing points in the H-alpha
chromospheric network. This disturbance is not a
chromospheric Moreton wave, but it does produce a temporary
activation of a transequatorial filament. This filament does
not erupt nor do any other filaments in the vicinity. MDI
magnetograms show that the brightened network points are all
of the same polarity (the dominant polarity among the points
in the disturbance's path), suggesting that the affected
field lines extend into the corona where they are energized
in sequence as the eruption tears away.

Three other similar eruptive events (non-transequatorial)
that we studied, while they are less impressive, show most
of the same phenomena including distant sympathetic flares
and a propagating disturbance showing close adherence to the
monopolarity rule. Two of these events do include filament
eruptions near the main flare. We conclude that the
observations of these four events are consistent with large
scale coronal eruptive activity that triggers nearly
simultaneous surface activity of various forms separated by
distances on the same scale as the coronal structures
themselves. A filament eruption at the main flare site
appears not to be a necessity in this type of eruptive
activity.